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===Major plates===
===Major plates===
These seven plates comprise the bulk of the continents and the [[Pacific Ocean]]. For purposes of this list, a '''major plate''' is any plate with an area greater than 10 million km<sup>2</sup>.
These ten plates comprise the bulk of the continents and the [[Pacific Ocean]]. For purposes of this list, a '''major plate''' is any plate with an area greater than 10 million km<sup>2</sup>.
* [[Pacific Plate]] – 103,300,000 km<sup>2</sup>
* [[Pacific Plate]] – 103,300,000 km<sup>2</sup>
* [[North American Plate]] – 75,900,000 km<sup>2</sup>
* [[North American Plate]] – 75,900,000 km<sup>2</sup>

Revision as of 02:16, 23 May 2015

Global earthquake epicentres, 1963–1998
The 15 major plates
Plate tectonics map from NASA

This is a list of tectonic plates on Earth. Tectonic plates are pieces of Earth's crust and uppermost mantle, together referred to as the lithosphere. The plates are around 100 km (62 mi) thick and consist of two principal types of material: oceanic crust (also called sima from silicon and magnesium) and continental crust (sial from silicon and aluminium). The composition of the two types of crust differs markedly, with basaltic rocks ("mafic") dominating oceanic crust, while continental crust consists principally of lower density granitic rocks ("felsic"). See also Plate tectonics.

Current plates

Geologists generally agree that the following tectonic plates currently exist on the Earth's surface with roughly definable boundaries. Tectonic plates are sometimes subdivided into three fairly arbitrary categories: major (or primary) plates, minor (or secondary) plates, and microplates (or tertiary plates).

Major plates

These ten plates comprise the bulk of the continents and the Pacific Ocean. For purposes of this list, a major plate is any plate with an area greater than 10 million km2.

Minor plates

These smaller plates are often not shown on major plate maps, as the majority do not comprise significant land area. For purposes of this list, a minor plate is any plate with an area less than 10 million km2 but greater than 1 million km2.

Microplates

These plates are often grouped with an adjacent major plate on a major plate map. For purposes of this list, a microplate is any plate with an area less than 1 million km2. Some models identify more minor plates within current orogens like the Apulian, Explorer, Gorda, and Philippine Mobile Belt plates. There may or may not be scientific consensus as to whether such plates should be considered distinct portions of the crust, thus new research could change this list.[1][2][3][4]

Ancient continental formations

In the history of Earth many tectonic plates have come into existence and have over the intervening years either accreted onto other plates to form larger plates, rifted into smaller plates, or have been crushed by or subducted under other plates (or have done all three).

Ancient supercontinents

A supercontinent is a landmass consisting of multiple continental cores. The following list includes the supercontinents known or speculated to have existed in the Earth's past:

Ancient plates and cratons

Not all plate boundaries are easily defined, this is especially true for ancient pieces of crust. The following list of ancient cratons, microplates, plates, shields, terranes, and zones no longer exist as separate plates. Cratons are the oldest and most stable parts of the continental lithosphere and shields are the exposed area of a craton(s). Microplates are tiny tectonic plates, terranes are fragments of crustal material formed on one tectonic plate and accreted to crust lying on another plate, and zones are bands of similar rocks on a plate formed by terrane accretion or native rock formation. Terranes may or may not have originated as independent microplates since a terrane may not contain the full thickness of the lithosphere.

African plate

Antarctica plate

Eurasian plate

Indo-Australian plate

Basic geological regions of Australia, by age.
Map of chronostratigraphic divisions of India

North American plate

North American cratons and basement rocks.

South American plate

References

  1. ^ Tetsuzo Seno, Taro Sakurai, and Seth Stein. 1996. Can the Okhotsk plate be discriminated from the North American plate? J. Geophys. Res., 101, 11305-11315 (abstract)
  2. ^ Bird, P. (2003). "An updated digital model of plate boundaries". Geochemistry, Geophysics, Geosystems 4 (3): 1027. doi:10.1029/2001GC000252. http://peterbird.name/publications/2003_PB2002/2003_PB2002.htm.
  3. ^ Timothy M. Kusky, Erkan Toraman, and Tsilavo Raharimahefa (2006-11-20). "The Great Rift Valley of Madagascar: An extension of the Africa–Somali diffusive plate boundary?". International Association for Gondwana Research Published by Elsevier B.V.{{cite news}}: CS1 maint: multiple names: authors list (link)
  4. ^ Niels Henriksen, A.K. Higgins, Feiko Kalsbeek and T. Christopher R. Pulvertaft (2000). "Greenland from Archaean to Quaternary" (PDF). No. 185. Greenland Survey Bulletin. Retrieved 2009-10-04.{{cite news}}: CS1 maint: multiple names: authors list (link)
  5. ^ http://www.civil.ist.utl.pt/cratera/intro.htm
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